ICP operates on two sets of points \(S\)  and \(S^{ref}\) , where \(S_i, S^{ref}_j \in \mathbf {R}^{n}\)  (usually \(n=2\)  or \(n=3\) ) , with initial proper rigid transformation guess \(u^0\) . The simplest algorithm variant [1]} can be described as follows:
